Crown block brake assembly



July 21, 1953- Filed Feb. 18, 1952 c. MCI. ROBERSON 2,646,251

CROWN BLOCK BRAKE ASSEMBLY 3Sheets-Sheet 1 INVENTOR. cpfiun}: ROBlZRSON BY WMMMWR ATTQBEEYS y 21, 1953 c. MOI. ROB'ERSON 2,646,251

CROWN BLOCK BRAKE ASSEMBLY Filed Feb. 18, 1952 s Sheets-Sheet 2 REMOTELY CONTROLLED un 0 SUPPLY 3% (v v INVENTOR. a? '5: CLAUDE M.ROB)3RSON rn BY z 3 Wm M M g M v Q rroazymys u y 21, 1953 c. MOI. ROBERSQN 2,646,251

CROWN BLOCK BRAKE ASSEMBLY Filed Feb. 18, 1952 s Sheets-Sheet s FIGQ. 2,

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2,646,251" P oRowN' ooK' RAKE ASSEMBLY Claude McInnis Roberson, Shreveport, La; Application Febr ary 18, 1952,Serial No. 272,091

' The present invention relates to oil well drilling apparatus and, more particularly, to apparatus for tensioning the drilling line of a drilling rig to prevent 'excessive wear of the line. '*The" usual rotary well' drilling apparatus com prises a draw works which includes a power driven storage drum located on the floor of the derrick, a crown block mounted on the top pl-at'' form of the derrick, and atraveling block movable'up and down within the derrick with respect to the crown block. The traveling block, and the crown block each comprise a plurality of sheaves which are rotatable with respect toone another, usually on common shafts. Theoil well hook assembly, used to support the elevators and 14 Claims. (01. '2'54 145) the line will force the upper layers of line on the drum down between the coils of the lower layers, thus causing abrasion between the coils of the line. The excess wear on the line resulting from such abrasion every time the weight supported by the line is increased causes the lineto wear out quite quickly. Since extreme danger to operating personnel would be caused if the line were to break suddenly because of} this abrasion, and since replacement of the line itself is extremely expensive, 'it is eminently desirable that some way be'found to avoidwinding the linearound the storage drumat different pipe carried by theelevato'rsis suspended from I the traveling block and movable; therewith, In order to provide for'movement of the traveling block and apparatus supported by it with respect to the derrick floor, 'a drilling line, usually a steel cable, is passed from the storage drum of the tensions at different times.

I, 'COnventiorialjdraw works have brakes on the power-driven drum 7 for controlling its rotational movements. If the brakes 'Wereapplied sudden ly while thejtraveling block was rising in the derrick, the momentum of the drill line would. tend to'keep it moving upwardly,sinc e' the line would be moving as fast" as 3100 fee't'perminute crown block. overthe fast-line sheave and down around one of the sheaves of the traveling block,

and is then roved back and forth between the the'traveling block to be moved up and down in the derrick with respect to the crown block.

The drill line is'subjected to widely-varying tensions at different times during the drilling operation. When only the traveling block,.the

hook assembly and the elevators are supported by the drill line, each line of an eight line stringup of drillline will be subjected to a pull of about 2000 pounds. When a stand of pipe is lifted by the elevator for attachment to the drilling string to lengthenthe string, the pull on each line will be increased by about '220 pounds. When the entire drilling string is supported by the elevator, as when the string is lifted to permit removal of stands of pipefrom the.string,,the tension on each line may be as high as 33,000 pounds, or-

more.

It is obvious that line wound'on'the storage I drum when only the hook assembly, the traveling and weighsapproximatelyfz pounds per foot. Consequently, slack line would be thrown to the storage drumycausing the outer coils'of line pre-' viously wound on the drum to'loosen so that a plurality of loose coils would be, wound. about the drum. When the brakes were next released, the weight of; the traveling block and other'ap paratus supported below the orownbl'ock'by the drill line would pull the line tight. However, because of the slack coils on the drum, the traveling block would drop suddenly as the coils tightened, thus causing the outer coils of line on'the drum to pull down between the coils of the inner layers of line. The snap caused by the sudden drop of the traveling block and the other. apparatus supported by it would cause excessive tension on the line and possibly cause breakage block, and the elevators are supported by the line, will be relatively loosely wound in comparison with line wound on the drum when the weight of ,a stand of pipe or of the entire drilling, string are also supported by the line. When the heavier weight of the pipe stand or the drilling string is put on the line, the added'tension on would be subject to'great abrasion between each 7 other because of their crossed condition, so that, even if the. linedid not snap because of the excessive tension caused by the sudden drop of the. apparatus supported by the line th -;1i

would be "damaged; V I I An'other'operation in which the tensio n of the drilling line is extremely important is replacing worn-out sections of drilling line with new line In this operation, the driller must lowerthe traveling block to the derrick floor, take the line off the sheaves of the traveling block, pull the worn-out section of line from the storage drum and cut it. The new section of line pulled on the storage drum is then wound on the sheaves of the traveling block. When the traveling block is raised ofi the derrick floor up to its normal position above the floor, it is necessary that the new line wound on the storage drum be held under such tension that the line is wound tightly on the drum.

A further operation in which it is extremely important that the line extending between the;

storage drum and the apparatus supported by the line and movable within the derrick, be kept at an even tension, is swabbingor coring. For

swabbing or coring operations, the line may be passed over a single stationary rotatable sheave mounted at the top of the derrick, Or it may be passed over oniy the fast-line sheave of the crown block and attached to the swabbing or corin tool. When first spooling the swabbing or coring line onto the storage drum, it is necessary that the line be kept tight on the drum, so that abrasion between the various coils of the line will not be caused by their movement relative to one another and relative to the storage. drum during later winding and unwinding operations. Also, when a swabbing tool is in use and is being pulled, the

well might'start producing fluid or gas at a fast rate, causing the swabbing tool to rise in the well hole faster than the line is being spooled on the storage drum. In such case, the line thrown to the drum would be slack, causing the outer coils on the drum to loosen, so that loops of loose line would lie on the derrick floor. These loose coils or loops would later be snapped up by the drum as the swabbing operation continued, and the whipping action of the loops as they were snapped up by the storage drum would make it extremely dangerous for personnel in the area.

Methods and apparatus for keeping the line taut between the storagedrum and theshea'v at the top of the derrick have been previously proposed but their operation has not been entirely successful. The apparatus of the present invention comprises means for opposing rotation of a stationary rotatable sheaveat the top of the derrick and means for urging the line against the rotatable sheave so that the line may not slip while the sheave is being held against rotation. More specifically, when the present invention is applied to a crown block utilized in connection with a traveling block, a brake is supplied for the fast-line sheave of the crown block and fluidoperable means for controlling the brake is provided. A pressure roller is also provided to urge the lineagainst the line-carrying groove of the fast-line sheave to prevent relative movement between the line and the sheave when the brake is applied to the sheave.

When the present invention is utilized in connection with a swabbing or coring tool, the brake band and pressure roller may be applied to a single stationary, rotatable sheave mounted at the top of the derrick. It is also contemplated that fluid under pressure, preferably, though not necessarily, air, for controlling the operation of the brake band and of the pressure roller be supplied, and that application of the fluid to operate the brake band and the pressure roller be controlled from a point remote from the rotatable sheave.

The apparatus'of the present invention will be more fully describedin conjunction with the ac-- companying drawings which show a preferred embodiment of the invention.

In the drawings:

1 is a diagrammatic representation of oil well drilling apparatus-including a crown block, to which the present invention may be applied;

Fig. 2 is a diagrammatic representation of oil well drilling apparatus, including a swabbing tool, to which the present invention may be applied;

Fi 3 is a side elevational view of a crown block having the apparatus of the present invention applied thereto;

Fig. i is a partial top view, partly in section, of the apparatus ofFig. 3;

Fig. 5 is a sectional view taken on line 5-5 of Fig. 3.

Conventional oil well drilling apparatus, as shown in Fig. 1, comprises a derrick I having a conventional draw works including a powerdriven storage drum 2 mounted on the derrick floor, a crown bl0ck 3 secured on a stationary support 4 on'a platform 5 at the top of the der rick, and the usual traveling block 5 suspended below the crown block. The usual drilling line 7 customarily a steel cable, extends between the storage drum and the crown block and is roved around the various component sheaves of the crown block and of the traveling block. In its passage from the storage drum, the line first passes over the outside sheave 8 of the crown block, then extends downwardly and over one of the sheaves of the traveling block and then extends back and forth between the successive sheaves oi the crown block and the traveling block. i'he bitter end of the line is fixed at 9 to the derrick floor, or it may be fixed to the derrick substructure.

In the apparatus shown in Fig. 2, the draw works, including thepower-driven storage drum 2 is mounted on the floor of the derrick I. Drilling line I extends between the storage drum and a swabbing tool it suspended within the derrick, the line passing over a sheave I i mounted for rotation on the top platform 5 of the derrick.

In Figs. 3 through 5, the crown block 3 is shown as having a plurality of sheaves rotatable with respect to one another on a shaft l2. shows two of these sheaves, indicated at 8 and 8, having drill line-carrying grooves 43 and i3. Sheave 8 is conventionally called the fast-line sheave, so-named because its rotational speed is higher than the rotational speed of the other sheaves of the crown block during movement of the traveling block relative the crown block.

Mounted on the fast-line sheave 8, is a brake flange l4, and a brake band I 5 is positioned about the brake flange for cooperation therewith. End it of the brake band'is bolted to the crown block support 4. A fluid-operable diaphragm I'Lhaving fluid line l8 for conducting fluid under pressure, preferably, though not necessarily, air, from a remotely controlled source H3 to the diaphragm, is mounted on the support l at the opposite side of the crown block from the end It of the brake band. A link l9 connects the diaphragm to one arm 29 of a bell crank lever 21. The other arm 22 of the bell crank lever is connected to the end 23 of the brake band. Consequently, when fluid underpressure is supplied to the fluid-operable diaphragm I 'l, the diaphragm moves in-- wardly toward the crown block, causing clockwise movement of the bell crank lever 2| and downward movement of the end 23 of the brake band. The brake band is thus caused to grip the brake flange l4.

Figmi A= bracket .24 is mounted on the support 4 on the opposite side of the crown block from the diaphragm IT. A casing 25' is journalled'on a shaft '26 mounted at the upper end'of the bracket '24; A pressure roller 21 is rotatably journalled in the casing 25 on a shaft 28 positioned below the shaft l2 of the crownblock opposite the groove IE1 in the fast-line sheave. .A second fluid-operable diaphragm 29, having a fluid line 30 for carrying fluidunder pressure from a remotely-controlled source 30' is mountedon the support '4 adjacent the lower. end: of the casing 25. A push rod 3| is connected to the diaphragm .and extends and is attached to the lower end of the casing for transmitting movement of'the diaphragm to the casing. The pressure roller 2:1 may be of steel, aluminum, hard copper, or any other suitable material.

In the operation. of the apparatus herein described as illustrative'of the present invention, when the traveling block, the hook assembly and the elevator are to be lifted within the derrick to pick up "a stand of drill pipe, power is supplied to the draw works to rotate the storage drum in such direction that drilling line is wound on the storage drum. Since the line is only carrying the relatively small weight of the traveling block, the hook assembly and the elevator at this time (approximately 2000 pounds on each line between the traveling block and the crown block), it is necessary to provide means for maintaining the line between the storage drum and the crown block under a higher tension than would result from the weight of the apparatus supported by the drill- .ing line. Fluid is supplied to the diaphragm l1,

causing the diaphragm to move toward the crown block, thus causing the bell crank lever 2| to move in a clockwise direction and pull the end 2 3 of the brake band l5 downwardly. The band is thereby moved into frictional contact with the brake flange l4, thus causing rotation of the.

fast-line sheaveB to be opposed. At the same time, fluid under pressure is 'appliedto .the diaphragm 29, causing the diaphragm to move toward the crown block, thus causing the push rod 3| and the casing 25' to move in the same between the line and the sheave, so that, even if the well begins pumping, the line will not un-'- wind in the storage drum to form loose coils,

but rather will be maintained. under. uniform high tension. 7 .It should berealized that the apparatus specifically described herein is only illustrative of the present invention and that many minor changes could be made in the.specific components of the apparatus without departingfrom the spirit of the invention. Accordingly, the invention is not to be considered to be limited to the apparatus specifically described, but rather is limited only by the scope of the appended claims. Moreover, though the term swabbing tool is utilized in describing the apparatus with which the present invention may be used, the invention should not be considered as limited to use with such a tool. Any apparatus or tool,

e. g.,- a coring tool, movable under a derrick by operable diaphragm to said brake band, means for supplying fluid under pressure to said fluidoperable diaphragm tomove it in such direction that the brake band is'moved intogripping engagement with the brake flange, whereby rotational movement of the fast-line sheave maybe opposed, a pressure roller positioned opposite As a result of this operation, more power has 7 to be supplied by the draw worksto the storage drum-in order to wind the drilling line on the storage drum. The greater power supplied to the storage drumputs the drilling line between the storage drum and the fast-line sheave of the crown block under a high tension (preferably between 3,000 pounds and 5,000 pounds, as appropriate), As a result of this high tension, the line is wound on the storage drum in uniform, closely-packed layers or coils, and when the additional weight ofthe pipe stand is put on the drilling line, the pressure applied to the drill-line-carrying surface of the fast-line sheave and movable toward the fast-line sheave 7 the fast-line sheave and the drilling line, whereby relative movement between the fast-line sheave and the drilling line may be opposed.

2. Apparatus. for tensioning the line between a power-driven storage drum about which the the diaphragm I! may be reduced, if such is de- 7 ported by the drilling line, fluid pressure may be released from diaphragms I! and 29, because the tension-increasing effect of the pressure roller and the brake band is not needed when comprising at least one stationary freely-rotatable sheave mounted in the derrick, said sheave having a line-carrying surface on which said line 'issupported, a brake flange mounted on said sheave, a brake band cooperable with the brake flange, fluid-operable means for movingthe brake band into gripping engagement with the brake flange, a pressure roller positioned opposite the line-carrying surface of the sheave and movable toward the sheave to oppose relative movement between the sheave and the line, and fluidoperablemeans fonmoving .the pressure roller toward the sheave.

3. Apparatus for guiding a line between a storage drum about which the line is wound and apparatus movable within an oil well derrick supported by the line, including a stationary freely rotatable sheave having a line-carrying surface on which the line is supported, means connected to the sheave operable to oppose rotation thereof, and means for urging the line against the sheaveto oppose relative movement between the line and thesheave.

4. Apparatus for guiding a line between a storage drum about which the line is wound and apparatus movable Within anoil well derrick supported by the line, including a stationary freely rotatable sheave having a line-carrying surface .on which the line is supported, a brake flange diaphragm to the brake band that supply of fluid under pressure to the diaphragm causes movement of the brake band into gripping engagement with the brake flange.

6,.Apparatus for guiding a line between a storage drum about which the line is Wound and apparatus movable within an oil well derrick supported by the line, including a stationary freely rotatable sheave having a line-carrying surface on which the line is supported, a brake flange mounted on-said sheave, a brake band cooperable with the brake flange having one end fixed and its other end movable with respect to the brake flange, a fluid-operable diaphragm, means linking the diaphragm to said other end of the brake band, and means for supplying fluid under pressure to the diaphragm to cause movement thereof in such direction that said movable end of the brake band moves to cause the brake band to grip the brake flange and oppose rotational movement of the sheave.

7. Apparatus as defined in claim 6 having a pressure roller positioned opposite the line-carrying surface of the sheave, a second fluid-operable diaphragm, means linking said second diaphragm to the pressure roller, and means for supplying fluid under pressure to said second diaphragm to cause movement of said second diaphragm, the linking means and the pressure roller in such direction that the pressure roller urges the line against said line-carrying surface of the sheave to oppose relative movement between the line and the sheave.

8. A crown block for guiding the drilling line of oil well drilling apparatus comprising 'a plurality of sheaves, including a fast-line sheave, each of said sheaves having a line-carrying surface, said plurality of sheaves being freely rotatable with respect to one another, means operable to oppose rotation of said fast-line sheave. and means for urging the drilling line against the linecarrying surface of the fast-line sheave to oppose relative movement between the drilling'line and the fastline sheave.

.9. A crown block as defined in claim 8 in which said rotation-opposing'means comprises a brake flange mounted on said fast-line sheave, a brake band cooperable with the brake flange, and means for moving the brake band into gripping engagement with the brake flange to oppose rotation of the fast-line sheave, and said drilling-line-urging means comprises a pressure roller positioned opposite the line-carrying surface of the fast-line sheave and movable toward the fastline sheave to move the drilling line against the fast-line sheave to oppose relative movement between the drilling line and the fast-line sheave.

10. A crown block'for guiding the drilling line of oil well drilling apparatus comprising a plurality of sheaves, including a fast-line sheave, each of said sheaves having a line-carrying surface, said plurality of sheaves being freely rotatable with respect to one another, a brake flange mounted on said fast-line sheave, a brake band cooperable with the brake flange, and means for moving the brake band into gripping engagement with the brake flange to oppose rotation of the fast-line sheave.

11. A crown block as defined in claim 10 in which said brake-band-moving means comprises a fluid-operable diaphragm, a remotely-controlled source of fluid under pressure connected to said diaphragm, and means so linking the diaphragm to the brake band that supply of fluid under pressure to the diaphragm causes movement of the brake band into gripping engagement with the brake flange.

12. Apparatus for tensioning the line between a power-driven storage drum about which the line is wound and a swabbing tool supported by the line and movable under an oil well derrick, comprising at least one stationary, freelyrotatable sheave mounted in the derrick, said sheave having a line-carrying surface on which said line is supported, means for opposing rotation of said sheave, and means for urging the line against the sheave to oppose relative movement between the sheave and the line.

13. Apparatus as defined in claim 12 in which said line-urging means comprises a pressure roller positioned opposite the line-carrying surface of the sheave and movable toward the sheave to urge the line against the sheave, and fluid-operable means for moving the pressure roller toward the sheave.

14. Apparatus for tensioning the line between a power-driven storage drum about which the line is wound and a swabbing tool supported by the line and movable under an oil well derrick, comprising at least one stationary, freelyrotatable sheave mounted in the derrick, said sheave having a line-carrying surface on which said line is supported, a brake flange mounted on said sheave, a brake band movable into gripping engagement with the brake flange, and fluid-operable means for moving the brake band into gripping engagement with the brake flange.

CLAUDE. McINNIS ROBERSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,473,606 Brandon Nov. 13, 1923 2,226,947 Sheldon Dec. 31, 1940 2,279,853 White Apr. 14, 1942 2,389,226 Woolslayer et a1. Nov. 20, 1945 2,564,457 Wilson Aug. 14, 1951 

